Child development is a holistic process multiply determined by complex interactions of individual and environmental properties. It is becoming increasingly obvious that child development cannot be understood by common data analysis procedures, where data are aggregated over individuals into some group-level forms, fragmented studies of relationships between a few variables torn out of the context of the whole, and studies that are either cross-sectional or conceptualize development as a quantitative change. This collection of empirical studies aims at understanding child development in early primary school by applying a consistently systemic, person-oriented developmental approach. An immensely complex web of developmental relationships between cognitive and non-cognitive processes in educational settings is emerging in the synthesis of the empirical contributions to this book.